pupil

Argyll Robertson pupil one that is miotic and responds to accommodation effort, but not to light.

fixed pupil a pupil that does not react either to light or on convergence, or in accommodation.

Hutchinson's pupil one that is dilated while the other is not.

tonic pupil a usually unilateral condition of the eye in which the affected pupil is larger than the other, responds to accommodation and convergence in a slow, delayed fashion, and reacts to light only after prolonged exposure to dark or light; see also adie's syndrome. Called also Adie's pupil.

pu·pil (p),

(pyū'pĭl), [TA]

The circular orifice in the center of the iris, through which the light rays enter the eye.

pupil

Argyll Robertson pupil one that is miotic and responds to accommodative effort, but not to light.

fixed pupil one that does not react either to light or on convergence, or in accommodation.

Hutchinson's pupil one that is dilated while the other is not.

tonic pupil a usually unilateral condition of the eye in which the affected pupil is larger than the other; responds to accommodation and convergence in a slow, delayed fashion; and reacts to light only after prolonged exposure to dark or light.

pupil

(pyo͞o′pəl)

n.

The apparently black circular opening in the center of the iris of the eye, through which light passes to the retina.

pu′pi·lar, pu′pil·lar·y(-pə-lĕr′ē) adj.

pupil

[pyo̅o̅′pəl]

Etymology: L, pupa, doll

a circular opening in the iris of the eye, located slightly to the nasal side of the center of the iris. Like the iris, the pupil lies posterior to the cornea and the anterior chamber of the eye and is anterior to the lens. Its diameter changes with contraction and relaxation of the muscular fibers of the iris as the eye responds to changes in light, emotional states, and autonomic stimulation. The pupil is the window of the eye through which light passes to the lens and the retina. See also dilator pupillae,sphincter pupillae. pupillary,adj.

pu·pil

(p) (pyū'pil) [TA]

The circular orifice in the center of the iris, through which light rays enter the eye. Synonym(s): pupilla [TA] .

[L. pupilla]

pupil

(pu'pil) [L. pupilla, little doll (the reflection in the pupil)]

PUPIL DILATION

The contractile opening at the center of the iris of the eye. It is constricted when exposed to strong light and when the focus is on a near object; is dilated in the dark and when the focus is on a distant object. Average diameter is 4 to 5 mm. The pupils should be equal. See: pupilla; illustration

Differential Diagnosis

Constriction of the pupil occurs, for example, in bright light and after exposure to drugs such as morphine, pilocarpine, physostigmine, eserine, and other miotics.

Dilation of the pupil is most often observed after treatment with mydriatic drugs (such as atropine, scopolamine, or homatropine), but may also be caused by paralysis of cranial nerve III, intracranial masses or trauma, sympathetic nervous system stimulation, and other pupillary stimuli.

Robertson pupil

stiff pupil

tonic pupil

pupil

The circular opening in the centre of the iris of the eye. The pupil becomes smaller (constricts) in bright light and widens in dim light under the action, respectively of its circular and radial muscle fibres.

pupil

the central opening in the iris of the vertebrate eye through which the light passes to the lens and retina. It changes in size as a result of muscle contraction and expansion moving the iris.

Pupil

The part of the eye that looks like a black circle in the center of the iris. It is actually an opening through which light passes.

pupil

Aperture within the iris, normally circular, through which light penetrates into the eye. It is located slightly nasally to the centre of the iris. Its diameter can vary from about 2 to 8 mm. It is often slightly smaller in old age. The function of the pupil is to regulate the amount of light admitted into the eye, to optimize the depth of focus and to mitigate ocular aberrations. Seeacorea; anisocoria; corectopia; dicoria; dyscoria; hippus; iridectomy; microcoria; miosis; dilator pupillae muscle; sphincter pupillae muscle; mydriasis; Edinger-Westphal nucleus; polycoria; polyopia; pupil light reflex.Adie's pupil A pupil in which the reactions to light, direct or consensual, are almost abolished, with a reaction occurring only after prolonged exposure to light or dark. The reaction of the pupil to a near target is also delayed and slow. The condition is usually unilateral, with the affected pupil being the larger of the two (anisocoria). It may be due to a disease of, or injury to, the ciliary ganglion or to the short ciliary nerves. Other causes include temporal arteritis in elderly patients, syphilis or diabetes. Syn. myotonic pupil; pupillotonia; tonic pupil (some authors use this last term when the cause is known and Adie's pupil when the cause is unidentified). Seeefferent pupillary defect; Adie's syndrome; pupil light reflex.amaurotic pupil Miotic pupil that does not react to direct and consensual ipsilateral light stimulation, but does react consensually to contralateral stimulation. It is most often noted in cases of severe optic nerve dysfunction or retinal disease.apparent pupilSeeentrance pupil of the eye.Argyll Robertson pupil Pupil that reacts when the eye accommodates and converges but fails to react directly and consensually to light. The condition is bilateral, the pupils are small and usually unequal. It is usually a sign of neurosyphilis. Seeiridoplegia; tabes dorsalis.artificial pupil1. Pupil made by iridectomy. 2. A circular aperture made in a diaphragm which can be mounted in front of the eye to provide a constant and smaller pupil size. It is used in research but also as a clinical test. Seepinhole disc.pupil blockSeepupillary block.pupil constrictionSeemiosis; pupil light reflex.pupil dilatationSeemydriatic; pupil light reflex.ectopic pupilSeecorectopia.entrance pupil of the eye This is the image of the iris aperture formed by the cornea. It is what one sees when one looks at an eye. It is some 13% larger than the real pupil and located slightly in front of it. Syn. apparent pupil (Fig. P23).exit pupil of the eye This is the image of the iris aperture formed by the crystalline lens. It is slightly larger (,3%) than the real pupil and situated slightly behind it (Fig. P23).Horner's pupilSeesyndrome, Horner's.Hutchinson's pupil A pupil that is dilated and completely inactive to all stimuli. It is associated with lesions of the central nervous system, as may occur in head injury.keyhole pupil A pupil shaped like a keyhole due to iridectomy in which a section of the iris extending from the pupillary margin to the periphery has been excised, or due to coloboma or trauma to the iris.pupil light reflexSeepupil light reflex.Marcus Gunn pupil A defect of the pupillary reflex characterized by a smaller constriction of both pupils when the affected eye is stimulated by light as compared to that occurring when the normal eye is stimulated. It is easier, however, to observe this phenomenon when swinging a light from one eye to the other in a darkened room while the subject is fixating a distant object (this is called the swinging flashlight test) (Fig. P24). Stimulation of the normal eye will cause constriction of both pupils whereas rapid stimulation of the affected eye will lead to a small dilatation (a paradoxical reaction, sometimes referred to as pupillary escape). This condition is due to a lesion in one retina or in one of the optic nerves, optic chiasma, optic tract, or the pretectal olivary nucleus that affects the afferent pupillary pathway. It is often the result of central or branch retinal or vein occlusion, extensive retinal detachment, retrobulbar optic neuritis, compressive optic neuropathy, or optic tract lesion, etc. Syn. relative afferent pupillary defect (RAPD), if the magnitude of the effect is partial; afferent pupillary defect (APD), if it is complete.myotonic pupilSeeAdie's pupil.pupil reflexSeepupil reflex.tonic pupilSeeAdie's pupil.white pupilSeeleukocoria.

Fig. P23 The entrance and exit pupils of the eye. E and E′ are the centres of the entrance and exit pupils, respectively (diagram not to scale)

*To stimulation of the affected eye.†When caused by an aneurysm of the posterior communicating artery.

pu·pil

(pyū'pil) [TA]

Circular orifice in center of iris, through which light rays enter eye.

[L. pupilla]

pupil

the aperture in the center of the iris which regulates the amount of light that reaches the retina.

Adie's pupil

dilated pupil due to parasympathetic denervation.

Argyll Robertson pupil

one that is miotic and responds to accommodation effort, but not to light.

fixed pupil

a pupil that does not react either to light or on convergence, or in accommodation.

multiple p's

polycoria.

occluded pupil

a congenital or acquired pupillary membrane that obstructs the pupil.

secluded pupil

a complete posterior synechia that separates the anterior and posterior chambers of the anterior compartment.

spastic pupil syndrome

anisocoria with pupils that fail to dilate in darkness. Seen in cats infected with feline leukemia virus. The virus has been observed in the short ciliary nerves and ciliary ganglia of some affected cats.

Ere long I had acquired as much facility in speaking French as set me at my ease with my pupils; and as I had encountered them on a right footing at the very beginning, and continued tenaciously to retain the advantage I had early gained, they never attempted mutiny, which circumstance, all who are in any degree acquainted with the ongoings of Belgian schools, and who know the relation in which professors and pupils too frequently stand towards each other in those establishments, will consider an important and uncommon one.

Washington's success is, then, not his teaching the pupils of Tuskegee, nor even gaining the support of philanthropic persons at a distance, but this--that every Southern white man of character and of wisdom has been won to a cordial recognition of the value of the work, even men who held and still hold to the conviction that a mere book education for the Southern blacks under present conditions is a positive evil.

Miss Sedley's papa was a merchant in London, and a man of some wealth; whereas Miss Sharp was an articled pupil, for whom Miss Pinkerton had done, as she thought, quite enough, without conferring upon her at parting the high honour of the Dixonary.

I had long since learnt to understand, composedly and as a matter of course, that my situation in life was considered a guarantee against any of my female pupils feeling more than the most ordinary interest in me, and that I was admitted among beautiful and captivating women much as a harmless domestic animal is admitted among them.

The school at which young Charley Hexam had first learned from a book--the streets being, for pupils of his degree, the great Preparatory Establishment in which very much that is never unlearned is learned without and before book--was a miserable loft in an unsavoury yard.

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